Heat dissipation module based on ultrathin heat conduction insulating layer and preparation method and application of heat dissipation module

Abstract

The invention relates to a heat dissipation module based on an ultrathin heat conduction insulating layer and a preparation method and application thereof, and relates to the technical field of circuit boards. The heat dissipation module comprises a first copper layer, a ceramic layer and a second copper layer. The first copper layer is located on one side of the ceramic layer, and the second copper layer is located on the other side of the ceramic layer; the thickness of the ceramic layer is 15-25 [mu] m; the thickness of the second copper layer is 8-12 [mu] m; the first copper layer is provided with a groove, and the groove is used for arranging a chip. The heat dissipation module is small in overall structure size, heat stress generated by thermal expansion and cold contraction is small, and an additional heat insulation layer does not need to be added.

Description

Technical Field

[0001] This invention relates to the field of circuit board technology, and specifically to a heat dissipation module based on an ultra-thin thermally conductive insulating layer, its preparation method, and its application. Background Technology

[0002] Existing heat dissipation structures with embedded circuits, such as Figure 1 As shown, its structure includes a thermally conductive copper base embedded in the inner layer of the circuit board, with the chip sintered onto the copper base. During operation, the chip dissipates heat primarily through the prepreg, the bottom copper base, and the heat dissipation holes beneath the copper base. The main process steps of this structure include: 1) etching the copper layer of the inner layer of the PCB circuit board to create circuitry; 2) drilling holes in the inner layer to form conductive vias; 3) slotting the inner copper layer and prepreg, with the slot dimensions suitable for embedding the copper base; 4) embedding the copper base containing the sintered chip; 5) laminating the outer prepreg and outer copper layer; 6) drilling holes in the outer copper layer to form conductive vias and heat dissipation holes; 7) fabricating the circuitry on the outer copper layer.

[0003] In existing technologies, the copper base embedded in the PCB circuit board requires an additional heat insulation layer, which is typically placed in... Figure 1 If the insulation layer below the bottom copper layer is made of organic materials, its thermal conductivity will be very low, which will weaken the overall structure's heat dissipation capacity. If ordinary ceramics are used as the insulation layer, a large ceramic layer is required, which will cause more severe thermal stress caused by thermal expansion and contraction. In addition, to ensure insulation properties, the thickness of ordinary ceramics will be >100μm, resulting in high thermal resistance. Summary of the Invention

[0004] To address the aforementioned issues, this invention provides a heat dissipation module based on an ultra-thin thermally conductive insulating layer. This heat dissipation module has a small overall structural size, low thermal stress caused by its own thermal expansion and contraction, and does not require the addition of an additional heat insulation layer.

[0005] This invention provides a heat dissipation module based on an ultra-thin thermally conductive insulating layer, comprising a first copper layer, a ceramic layer, and a second copper layer; the first copper layer is located on one side of the ceramic layer, and the second copper layer is located on the other side of the ceramic layer; the thickness of the ceramic layer is 15-25 μm; and the thickness of the second copper layer is 8-12 μm. The first copper layer has a groove for mounting the chip.

[0006] In one embodiment, the ceramic layer is bonded to the first copper layer by sintering, and the second copper layer is deposited on the other side of the ceramic layer by physical vapor deposition.

[0007] In one embodiment, the ceramic layer is made of a highly thermally conductive insulating ceramic material.

[0008] In one of the embodiments, the high-thermal-conductivity insulating ceramic material comprises at least one of aluminum oxynitride ceramic, boron nitride ceramic, silicon nitride ceramic, silicon carbide ceramic, beryllium oxide ceramic, and polycrystalline diamond ceramic.

[0009] In one of the embodiments, the chip is fixed in the groove by sintering. The sintering layer of the sintering is arranged on one side of the chip, and a metal layer is arranged on the other side of the chip, which is used to form electrical connection with the copper layer in the circuit board.

[0010] In one of the embodiments, the sintering layer comprises sintered silver, and the metal layer comprises copper.

[0011] The application further provides a preparation method of the heat dissipation module, comprising the following steps: slotting a copper base to form a first copper layer with a groove, wherein the groove is used to arrange a chip; sintering a ceramic layer on the bottom surface of the first copper layer, and depositing a second copper layer on the bottom surface of the ceramic layer by physical vapor deposition.

[0012] In one of the embodiments, the chip is sintered in the groove by a sintering layer, and a metal layer is plated on the other side of the chip away from the sintering layer.

[0013] The application further provides a circuit board comprising a heat dissipation structure of embedded circuit, wherein the heat dissipation structure of embedded circuit comprises the heat dissipation module.

[0014] The application further provides a preparation method of the circuit board, comprising the following steps: removing the copper layer of a predetermined area of a core board, wherein the predetermined area is used to embed the heat dissipation module; slotting and removing the filling material of the predetermined area; pasting a support layer; embedding the heat dissipation module; pressing and bonding the adhesive sheet and the copper layer; removing the support layer; pressing and bonding the adhesive sheet and the copper layer; drilling; forming conductive vias and heat dissipation holes; punching the copper layer; etching the outer layer circuit; pressing and bonding the adhesive sheet and the outer copper layer; drilling and etching the circuit of the outer copper layer; and surface treatment of the outer copper layer, to obtain the circuit board.

[0015] The application further provides application of the heat dissipation module in the circuit board.

[0016] Compared with the prior art, the application has the following beneficial effects: The heat dissipation module based on the ultra-thin thermal-conductivity insulating layer has small overall structure size, small thermal stress caused by thermal expansion and cold contraction, and no need to add an additional thermal insulation layer. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 FIG. 1 is a schematic diagram of a heat dissipation structure of embedded circuit in the prior art. Figure 2 A cross-sectional structure diagram of the heat dissipation module in Example 1 is shown in the figure. Figure 3 A preparation process flow chart of the heat dissipation module in Example 1 is shown in the figure. Figure 4 A cross-sectional structure diagram of the circuit board in Example 2 is shown in the figure. Figure 5 A preparation process flow chart of the circuit board in Example 2 is shown in the figure. Wherein, 1 is a chip, 11 is a sintering layer, 12 is a metal layer, 2 is a copper base, 3 is a conductive via, 4 is a heat dissipation hole, 5 is a semi-cured sheet, 6 is a copper layer, 71 is a first copper layer, 72 is an aluminum nitride ceramic layer, 73 is a second copper layer, 8 is a PCB, 81 is a surface metal layer, 82 is an adhesive sheet, 83 is ink, 84 is copper layer 1, 85 is copper layer 2, 86 is copper layer 3, 87 is copper layer 4, 88 is copper layer 5, 89 is copper layer 6, and 9 is a core plate. DETAILED DESCRIPTION

[0018] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application herein are only for the purpose of describing the specific embodiments and are not intended to limit the present application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0020] The reagents, materials and equipment used in the present embodiments are commercially available unless otherwise specified. The test methods are conventional test methods in the art unless otherwise specified.

[0021] Example 1 A heat dissipation module based on an ultra-thin heat-conducting insulating layer and a preparation method thereof.

[0022] I. The structure of the heat dissipation module.

[0023] As Figure 2As shown, from top to bottom, it includes a metal layer, a chip, a sintering layer, a first copper layer, an aluminum oxynitride ceramic layer and a second copper layer. The aluminum oxynitride ceramic layer is sintered on the bottom surface of the slotted first copper layer, and the second copper layer is deposited on the surface of the aluminum oxynitride ceramic layer by physical vapor deposition (PVD) technology. The first copper layer, the aluminum oxynitride ceramic layer and the second copper layer constitute the heat dissipation base of the chip, the chip is sintered at the slotted position of the first copper layer, and the chip surface is plated with a metal layer.

[0024] II. The preparation method of the heat dissipation module.

[0025] The process steps can be implemented as follows, as shown in the following figure: Figure 3 1) Cutting the raw material copper of the first copper layer; 2) Slotting the first copper layer, the slot size is suitable for chip sintering; 3) Sintering the aluminum oxynitride ceramic layer on the bottom surface of the slotted first copper layer; 4) The second copper layer is deposited on the surface of the aluminum oxynitride ceramic layer by physical vapor deposition (PVD) technology; 5) Chip sintering at the slotted position of the first copper layer; 6) Chip surface plating with a metal layer.

[0026] In this embodiment, the aluminum oxynitride ceramic layer material includes but is not limited to aluminum oxynitride ceramic, or other high-thermal-conductivity insulating materials (such as boron nitride) are used instead, which also have the same effect.

[0027] In this embodiment, the second copper layer can be deposited on the surface of the aluminum oxynitride ceramic layer by physical vapor deposition (PVD) technology under the condition of 500°C temperature, but is not limited to this, or other process technologies are used instead, which also have the same effect.

[0028] In this embodiment, the sintering layer of the chip includes but is not limited to sintered silver.

[0029] In this embodiment, the material of the metal layer includes but is not limited to copper.

[0030] Preferably, the thickness of the aluminum oxynitride ceramic layer can be 20μm.

[0031] Preferably, the thickness of the second copper layer can be 10μm.

[0032] III. Conclusion.

[0033] ​The conventional single heat dissipation copper base (only copper) in the prior art needs to be additionally matched with a high-thermal-conductivity high-voltage-resistance heat insulation layer to evenly dissipate heat for a high-power chip; if the heat dissipation base is made of ordinary ceramic such as alumina or aluminum nitride as the heat insulation layer (copper + ordinary ceramic + copper), some technicians form a heat dissipation module by "copper layer + insulation layer + copper layer", but this is realized by DBC or AMB process to realize thermal connection, and the copper layer is thick, so the thermal stress caused by thermal expansion and contraction is relatively serious; and to ensure the insulation property, the thickness of the insulation layer ceramic is >100 μm, and the thermal resistance is large.

[0034] In the present application, high-thermal-conductivity insulation ceramic material is used as the heat-conducting insulation layer, for example, the super-thin aluminum oxynitride ceramic used in the present embodiment, the aluminum oxynitride ceramic has a breakdown voltage >10 kV, so the thickness of the aluminum oxynitride ceramic layer can be very thin, and the thermal resistance is small, wherein the super-thin aluminum oxynitride ceramic layer can be coated and co-sintered on the first copper layer by the gradient transition layer method (first, copper base pretreatment, then preparation of the gradient transition layer, and finally co-sintering); the aluminum oxynitride ceramic has small density, high thermal conductivity (10-30 W / (m*K)), and better bending strength, corrosion resistance and oxidation resistance than ordinary alumina and aluminum nitride ceramic; the aluminum oxynitride ceramic has small thermal expansion coefficient, and the thermal stress caused by thermal expansion and contraction is small.

[0035] Furthermore, the thickness of the aluminum oxynitride ceramic layer and the second copper layer formed on the surface of the aluminum oxynitride ceramic layer by physical vapor deposition technology in the present application are both super-thin (μm level), the thermal stress generated is small, and the heat conduction performance is also better.

[0036] In addition, the design structure of the present application is implemented by being embedded in a PCB board, and the super-thin thickness of the aluminum oxynitride ceramic layer and the second copper layer can meet the overall thickness limit requirement of the PCB board, without being used as an external packaging substrate as in the conventional technology, which causes all the layers to be very thick, finally reaching mm level.

[0037] Embodiment 2 A circuit board.

[0038] The circuit board is prepared based on the heat dissipation module of embodiment 1, and the structure schematic diagram of the circuit board is as shown in Figure 4 , and the process flow of the preparation method is as shown in Figure 5 .

[0039] The circuit board is obtained by embedding the heat dissipation module structure based on the super-thin heat-conducting insulation layer prepared in embodiment 1 in the PCB circuit board core board layer position, which can be realized according to the following conventional process steps: 1) The core board removes part of the copper layer 3 and the copper layer 4 on the surface according to the size of the module; 2) The core board is slotted and opened, and the size of the slot is suitable for embedding the heat dissipation module; 3) Paste support; 4) embed the ultra-thin heat-conducting insulation layer into the heat-dissipation module; 5) press the adhesive sheet and the copper layer 2; 6) remove the support; 7) press the adhesive sheet and the copper layer 5; 8) drill holes to form conductive vias and heat-dissipation holes; 9) punch holes in the copper layer 2 to the copper layer 5; 10) etch the outer layer circuit (copper layer 2 and copper layer 5); 11) press the adhesive sheet, the copper layer 1 and the copper layer 6; 12) drill holes and etch the outer layer copper layer (copper layer 1 and copper layer 6) to form a circuit; surface treatment of the outermost copper layer, including plating a surface metal layer and coating a solder resist ink layer Any technical features of the above-described embodiments can be combined, and for the sake of brevity, not all possible combinations of the technical features in the above-described embodiments are described, however, as long as the combinations of the technical features do not contradict each other, they should be considered within the scope of the present disclosure.

[0040] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of variations and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the present application should be subject to the appended claims.

Claims

1. A heat dissipation module based on an ultra-thin thermally conductive insulating layer, characterized in that, It includes a first copper layer, a ceramic layer, and a second copper layer; the first copper layer is located on one side of the ceramic layer, and the second copper layer is located on the other side of the ceramic layer; the thickness of the ceramic layer is 15-25 μm; the thickness of the second copper layer is 8-12 μm. The first copper layer has a groove for mounting the chip.

2. The heat dissipation module according to claim 1, characterized in that, The ceramic layer is bonded to the first copper layer by sintering, and the second copper layer is deposited on the other side of the ceramic layer by physical vapor deposition.

3. The heat dissipation module according to claim 1, characterized in that, The ceramic layer is made of a highly thermally conductive insulating ceramic material.

4. The heat dissipation module according to claim 3, characterized in that, The high thermal conductivity insulating ceramic material includes at least one of the following: aluminum oxynitride ceramic, boron nitride ceramic, silicon nitride ceramic, silicon carbide ceramic, beryllium oxide ceramic, and polycrystalline diamond ceramic.

5. The heat dissipation module according to claim 1, characterized in that, The chip is fixed in the groove by sintering; The sintered layer is located on one side of the chip, and a metal layer is located on the other side of the chip. The metal layer is used to form an electrical connection with the copper layer in the circuit board.

6. A method for preparing the heat dissipation module according to any one of claims 1-5, characterized in that, Includes the following steps: Grooves are cut into the copper base material to form a first copper layer with grooves, the grooves being used to set the chip; A ceramic layer is sintered onto the bottom surface of the first copper layer, and a second copper layer is deposited on the bottom surface of the ceramic layer by physical vapor deposition.

7. The preparation method according to claim 6, characterized in that, The chip is sintered in the groove through a sintering layer, and a metal layer is plated on the other side of the chip away from the sintering layer.

8. A circuit board, characterized in that, The heat dissipation structure includes an embedded circuit, wherein the heat dissipation structure of the embedded circuit includes the heat dissipation module according to any one of claims 1-5.

9. The method for manufacturing the circuit board according to claim 8, characterized in that, Includes the following steps: Remove the copper layer from a predetermined area of ​​the core board, the predetermined area being used to embed the heat dissipation module, remove the filling material in the predetermined area by slotting, attach a support layer, embed the heat dissipation module, press the adhesive sheet and copper layer together, remove the support layer, press the adhesive sheet and copper layer together again, drill holes to form conductive vias and heat dissipation holes, make through holes in the copper layer, etch the outer layer circuitry, press the adhesive sheet and outer copper layer together, drill holes in the outer copper layer and etch the circuitry, and perform surface treatment on the outer copper layer to obtain the circuit board.

10. The application of the heat dissipation module according to any one of claims 1-5 in a circuit board.

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